Hybrid vehicle driving device

Abstract

A hybrid vehicle driving device includes: a first differential mechanism connected to an engine and transmitting a rotation of the engine; a second differential mechanism connecting the first differential mechanism and a drive wheel; engagement devices changing a speed of the first differential mechanism; and a valve arranged in a hydraulic circuit and regulating the engagement devices from simultaneously engaging. The second differential mechanism includes a first rotation element connected to an output element of the first differential mechanism, a second rotation element connected to a first rotating machine, and a third rotation element connected to a second rotating machine and the drive wheel. The valve regulates the engagement devices from simultaneously engaging at a time of traveling with the engine, and tolerates the engagement devices from simultaneously engaging at a time of traveling with the first rotating machine and the second rotating machine.

The invention claimed is: 
     
       1. A hybrid vehicle driving device comprising:
 a first differential mechanism connected to an engine and transmitting a rotation of the engine; 
 a second differential mechanism connecting the first differential mechanism and a drive wheel; 
 a plurality of engagement devices changing a speed of the first differential mechanism; and 
 a valve arranged in a hydraulic circuit supplying a hydraulic pressure to the plurality of engagement devices, and selectively preventing the plurality of engagement devices from simultaneously engaging; and 
 an electronic control unit configured to control the valve to switch a state of preventing the plurality of engagement devices from simultaneously engaging and a state of allowing the plurality of engagement devices to simultaneously engage, wherein 
 the second differential mechanism includes a first rotation element connected to an output element of the first differential mechanism, a second rotation element connected to a first rotating machine, and a third rotation element connected to a second rotating machine and the drive wheel, 
 the electronic control unit is configured to control the valve to prevent the plurality of engagement devices from simultaneously engaging at a time of traveling with the engine as a power source, and control the valve to allow the plurality of engagement devices to simultaneously engage at a time of traveling with the first rotating machine and the second rotating machine as the power source. 
 
     
     
       2. The hybrid vehicle driving device according to  claim 1 , wherein the electronic control unit is configured to control valve to further prevent the plurality of engagement devices from simultaneously engaging at a time of traveling with the second rotating machine as a single power source. 
     
     
       3. The hybrid vehicle driving device according to  claim 1 , wherein the plurality of engagement devices are configured to regulate a rotation of at least one of the output element and the engine by simultaneously engaging. 
     
     
       4. The hybrid vehicle driving device according to  claim 1 , further comprising:
 a first oil pump supplying a hydraulic pressure with respect to the plurality of engagement devices by being driven by the rotation of the engine; and 
 a second oil pump supplying a hydraulic pressure with respect to the plurality of engagement devices and the valve by being driven at a time the engine is stopped, wherein 
 the valve is configured to prevent the plurality of engagement devices from simultaneously engaging at a time the hydraulic pressure of the first oil pump is supplied, and to allow the plurality of engagement devices to simultaneously engage at a time the hydraulic pressure of the second oil pump is supplied. 
 
     
     
       5. A control method of controlling a hybrid vehicle driving device including a first differential mechanism connected to an engine and transmitting a rotation of the engine, a second differential mechanism connecting the first differential mechanism and a drive wheel, a plurality of engagement devices changing a speed of the first differential mechanism, and a valve arranged in a hydraulic circuit supplying a hydraulic pressure to the plurality of engagement devices and selectively preventing the plurality of engagement devices from simultaneously engaging, the second differential mechanism including a first rotation element connected to an output element of the first differential mechanism, a second rotation element connected to a first rotating machine, and a third rotation element connected to a second rotating machine and the drive wheel, the control method comprising:
 determining a traveling mode of the hybrid vehicle; and 
 controlling the valve to prevent the plurality of engagement devices from simultaneously engaging at a time of traveling with the engine as a power source, and controlling the valve to allow the plurality of engagement devices to simultaneously engage at a time of traveling with the first rotating machine and the second rotating machine as the power source. 
 
     
     
       6. The control method according to  claim 5 , further comprising:
 controlling the valve to prevent the plurality of engagement devices from simultaneously engaging at a time of traveling with the second rotating machine as a single power source.